Method and device for suppressing a transmitting signal in a receiver of an RFID write/read unit
First Claim
1. A method for operating an RFID read/write unit with transmitting signal suppression, the method comprising:
- providing the RFID read/write unit, the RFID read/write unit comprising a radio frequency part including a transmitter and a receiver, and a baseband part based on digital signal processing;
producing an amplitude and phase weighted copy of a transmitting signal, namely a compensation signal, with the baseband part; and
after linear modulation of the compensation signal, subtracting in an addition stage a resultant signal at an input of the receiver from a spurious coupling signal between the transmitter and the receiver, the transmitting signal having an auxiliary signal impressed upon a carrier signal from the RFID read/write unit with a frequency offset fd, for the purpose of processing without any DC voltage in the receiver downstream of an RX converter;
wherein the input of the receiver comprises a turn-on and turn-off attenuation element which, when turned on, protects the radio frequency part against overdrive or against intermodulation in the RX converter so that weights can be ascertained for the copy of the transmitting signal and direct rejection of the coupling signal is achieved, the attenuation element subsequently being turned off and the RFID read/write unit changing to an operating mode and performing permanent readjustment of the transmitting signal suppression.
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Accused Products
Abstract
A method and apparatus is disclosed for operating an RFID read/write unit with transmitting signal suppression. The RFID read/write unit comprises a radio frequency part including a transmitter and a receiver, and a baseband part based on digital signal processing. The method involves producing an amplitude and phase weighted copy of a transmitting signal, namely a compensation signal, with the baseband part. After linear modulation of the compensation signal, a resultant signal at an input of the receiver is subtracted in an addition stage from a spurious coupling signal. The transmitting signal has an auxiliary signal impressed upon a carrier signal from the RFID read/write unit with a frequency offset fd, for the purpose of processing without any DC voltage in the receiver downstream of an RX converter. The input of the receiver comprises a turn-on and turn-off attenuation element which protects the radio frequency part.
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Citations
11 Claims
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1. A method for operating an RFID read/write unit with transmitting signal suppression, the method comprising:
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providing the RFID read/write unit, the RFID read/write unit comprising a radio frequency part including a transmitter and a receiver, and a baseband part based on digital signal processing; producing an amplitude and phase weighted copy of a transmitting signal, namely a compensation signal, with the baseband part; and after linear modulation of the compensation signal, subtracting in an addition stage a resultant signal at an input of the receiver from a spurious coupling signal between the transmitter and the receiver, the transmitting signal having an auxiliary signal impressed upon a carrier signal from the RFID read/write unit with a frequency offset fd, for the purpose of processing without any DC voltage in the receiver downstream of an RX converter; wherein the input of the receiver comprises a turn-on and turn-off attenuation element which, when turned on, protects the radio frequency part against overdrive or against intermodulation in the RX converter so that weights can be ascertained for the copy of the transmitting signal and direct rejection of the coupling signal is achieved, the attenuation element subsequently being turned off and the RFID read/write unit changing to an operating mode and performing permanent readjustment of the transmitting signal suppression. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. An apparatus for transmitting signal suppression, the apparatus comprising:
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an RFID read/write unit, the RFID read/write unit comprising a radio frequency part and baseband part; wherein the radio frequency part includes a transmitter and a receiver; wherein the baseband part is based on digital signal processing and is configured to produce an amplitude and phase weighted copy of a transmitting signal, namely a compensation signal; wherein, after linear modulation of the compensation signal, the receiver is configured to subtract a resultant signal delivered to an input of the receiver from a spurious coupling signal between the transmitter and the receiver, the transmitting signal having an auxiliary signal impressed upon a carrier signal from the RFID read/write unit with a frequency offset fd, for the purpose of processing without any DC voltage in the receiver downstream of an RX converter; a turn-on and turn-off attenuation element provided in the receiver, wherein the attenuation element, when turned on, is configured to protect the radio frequency part against overdrive or against intermodulation in the RX converter so that weights can be ascertained for the copy of the transmitting signal and direct rejection of the coupling signal is achieved, and wherein, when the attenuation element is subsequently turned off, the RFID read/write unit changes to an operating mode and performs permanent readjustment of the transmitting signal suppression. - View Dependent Claims (10, 11)
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Specification